Rate of RB

Figure 11. Temperature effect on ET rates of Rb. capsulatas and its mutants. The data are reproduced from Ref. 6.

Figure 2. Rate of Rb uptake by obsidian from recirculating column experiments at different temperatures. Straight lines are least square regressions to Equation 1.

Salt Transport. The effects of ozone on membrane permeability can also be assessed by estimating salt leakage from treated tissue. In one study, susceptible bean plants were allowed to take up RbCl for 24 hr prior to ozone exposure. After exposure, leaf discs were placed in a desorption solution containing 0.5 M CaSOi and 2 mM KCl and the rate of Rb leakage into the desorption solution was determined. The initial loss was indistinguishable between treated and untreated plants and we assume that it represented exchange from free space. Then, for an extended period, treated tissue exhibited a linear loss of... 

When ozone is turned-off at some point during this rapid loss period, the high rate of Rb leakage ceases within 2-3 min and returns to the control leakage rate. Thus, this permeability change, measured by efflux, appears to be reversible, as is net K+ leakage measured with the cation electrode. ... 

A to B. Ion B has a total decay rate of RB. The differential equations for this coupled system are... 

The conception rate of Rb-deficient goats was significantly less than that of control. 

The Rb-poor nutrition influenced the number of goats without heat and the number of unsuccessful first inseminations only insignificantly, though clearly (Table 1.4-7). The conception rate of Rb-deficient goats was significantly less than that of controls, but the most important point noted was the extremely high abortion and miscarriage rates in the Rb-deficient animals. 

By measuring the rate of Rb efflux from excised and preloaded cucumber cotyledons, AFM injury was detected at concentrations as low as 10 nM ( ). Also, because AFM has an absolute requirement of light for expression of herbicidal activity, plant tissues can be pretreated in darkness without injury. Then, following light-activation, damage can be detected in relatively short time periods (10 to 15 min) (1 ). We believe these observations are indicative of its primary biochemical mechanism of action. 

Henry Rozengurt and I found that serum addition rapidly increases the influx rate of Rb into quiescent 3T3 cells. I should explain that 3T3 is a tissue culture cell line developed by George Todaro and Howard Green. Cells grow in a monolayer on the surface of plastic dishes. When these particular cells cover the surface of the plastic dish, growth stops, and the cells are said to enter a quiescent phase . The protein content of different dishes at this stage is remarkably uniform. This makes possible a very simple assay for transport of an element or compound containing a radioactive label. One simply incubates the cells on the dish with isotope in a suitable medium, sucks off the medium quickly, washes with saline which is also removed by suction and then extracts the accumulated radioactivity with dilute trichloracetic acid. Radioactivity in the acid-soluble pool is measured by conventional methods. 

Henry Rozengurt and I found that the increase in rate of Rb influx produced by serum is markedly sensitive to ouabain. So is the basal rate. This specific inhibitor decreases the rate of influx by 90%. When the concentration of K in the medium is reduced 10-fold, there is a striking increase in sensitivity to ouabain of both the stimulated and the basal rates. This would be expected if the changes in Rb uptake are largely mediated by fluctuations in the activity of the Na-K pumps , where K competes with ouabain. 

There are other aspects of the story, for example the fact that cyclic AMP also causes an extremely rapid, although smaller increase in rate of Rb uptake. However, space does not allow me to go into these matters. Let me summarize, then, by saying that serum has a remarkable effect upon quiescent 3T3 cells. In just a few minutes it causes the rate of entry of potassium (actually measured by using Rb) to increase by up to 3.5-4-fold. The effect is on Fmaz and is not due to synthesis of new transporter molecules. The stimulation is rapidly reversible on removal of serum, as if a switch were turned on and off—as if the transporter molecules were being rapidly uncovered and covered again. The effect is sensitive to ouabain, a specific inhibitor of the sodium-K pump. There is also an inhibition of initiation of DNA synthesis by ouabain, which is influenced by the level of K in the medium. It is presumed that a critical ionic environment is necessary for the events concerned in initiation of DNA synthesis, and the Na-K pump is involved in maintenance of this environment. 

Figure 10. Relaxation rates of Rb as a function of concentration in aqueous RbF, RbCl, RbBr, and Rbl.<22 ...

Alkaline solutions consisting of approximately 160 g/L NaAlnO and 60 g/L NaOH at 75°C and contact times in the range of 15 minutes, exhibit high etch rates for printed circuit boards (252,253). The resulting manganese residues can readily be removed by acid neutrali2ation. Addition of K", Rb", and Cs" as co-ions to an alkaline NaAlnO solution maintains etch rates of resin substrates comparable to solutions of higher NaAlnO concentrations (254). 

During the initial stages (when a < 0.04) of the thermal decompositions of the alkali (Na, K, Rb, Cs) perchlorates [845] (giving MC103), the rates of oxygen evolution from all four salts were approximately the same and independent of particle size and sample mass. Experimental values of E ( 190 kJ mole-1) were low compared with those found by Solymosi [846] for the overall reaction (250—290 kJ mole-1) and also lower than the standard enthalpies for anion breakdown (276—289 kJ mole-1) for... 

Since, in both these reactions (i.e. KI or Rbl and Agl), product formation occurs on both sides of the original contact interface, it is believed that there is migration of both alkali metal and silver ions across the barrier layer. Alkali metal movement is identified as rate limiting and the relatively slower reaction of the rubidium salt is ascribed to the larger size and correspondingly slower movement of Rb+. The measured values of E are not those for cation diffusion alone, but include a contribution from... 

ATPase also catalyzed a passive Rb -Rb exchange, the rate of which was comparable to the rate of active Rb efflux. This suggested that the K-transporting step of H,K-ATPase is not severely limited by a K -occluded enzyme form, as was observed for Na,K-ATPase. Skrabanja et al. [164] also described the reconstitution of choleate solubilized H,K-ATPase into phosphatidylcholine-cholesterol liposomes. With the use of a pH electrode to measure the rate of H transport they observed not only an active transport, which is dependent on intravesicular K, but also a passive H exchange. This passive transport process, which exhibited a maximal rate of 5% of the active transport process, could be inhibited by vanadate and the specific inhibitor omeprazole, giving evidence that it is a function of gastric H,K-ATPase. The same authors demonstrated, by separation of non-incorporated H,K-ATPase from reconstituted H,K-ATPase on a sucrose gradient, that H,K-ATPase transports two protons and two ions per hydrolyzed ATP [112]. 

FIGURE 14.4 Rate of decay of 02 against (3-CRYP concentration in air-saturated solutions of DPPC unilamellar liposomes using either RB or PBA as ()2 sensitizer. 

The vibrational frequency of the special pair P and the bacteriochlorophyll monomer B have also been extracted from the analysis of the Raman profiles [39,40,42,44,51]. Small s group has extensively performed hole-burning (HB) measurements on mutant and chemically altered RCs of Rb. Sphaeroides [44,45,48-50]. Their results have revealed low-frequency modes that make important contribution to optical features such as the bandwidth of absorption line-shape, as well as to the rate constant of the ET of the RCs. 

An example of light-assisted transport of the first type involves (200) as the carrier in the liquid membrane. In this case, irradiation of the membrane alternatively with UV and visible light significantly increases the rate of K+ and Rb+ transport in the presence of picrate ion. This system also exhibits discrimination since the transport of K+ is favoured over Rb+ (Shinkai, Shigematsu, Sato Manabe, 1982). 

For reaction (A), the rate may be written in terms of ( -rB) or ( -rc) instead of ( -rA). These rates are related to each other through the stoichiometry, as described in Section 1.4.4. Corresponding rate constants kB or kc may be introduced instead of kA, and these rate constants are similarly related through the stoichiometry. Such changes do not alter the form of equation 3.1-2 or values of a, fi, and y it is a matter of convenience which species is chosen. In any case, it should clearly be specified. Establishing the form of equation 3.1-2, including the values of the various parameters, is a matter for experiment. 

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